daintree



(No Model.)

B. H. DAINTREE.

DENTAL JAW PROP.

No. 410,665. Patented Sept. 10, 1889.

UNITED STATES PATENT ()FFIcE.

ROBERT H. DAINTREE, OF NE\V YORK, N. Y.

DENTAL JAW-PROP.

SPECIFICATION forming part of Letters Patent No. 410,665, dated September 10, 1889.

Application filed January 25, 1889- Serial No. 297,540. (No model.)

T0 (6 whom it may concern:

Be it known that 1, ROBERT II. DAINTREE, a subject of the Queen of Great Britain, re siding at New York city, county and State of New York, have invented certain new and useful Improvements in Dental J aw-Props, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, and to the letters of reference marked thereon.

My invention relates chiefly to that class of implements employed by dentists and othersfor propping the jaws of patients, as when administering gas or performing dental work, which implements may also be used in various surgical and analogous operations.

The object of my invention is to provide a prop of the character or class named, which shall be adjustable in the direction of its length, from the shortest length required to the longest, and include a yielding spring between its extremities to retain it in place and afford desirable elasticity, to make the prop of few and simple parts, which are not liable to get out of order, which may be easily and quickly made and assembled, and to secure other and further advantages in the matters of construction and operation, as will hereinafter appear.

To accomplish all of this my improvements involve certain new and useful arrangements or combinations of parts and peculiarities of construction, which will be herein first fully described, and then pointed out in the claims.

In the accompanying drawings, forming part of this specification, Figure l is a view in elevation, and Fig. 2 an axial section and elevation, of my improved dental jaw-prop.

Fig. 3 is a view like Fig. 2, but showing the parts partially extended in accordance with my invention.

In all these figures like letters of reference, wherever they occur, indicate corresponding parts.

A A are the cushions upon which the teeth or the jaws of the patient may bear. These are generally made somewhat pliable, as of rubber or cork, or they may be made of felt or any other substance desired.

B B are the heads or sockets intended to receive the cushions, which cushions may be applied or secured in place in any way.

lIeretot'ore in this general class of implements the cushion-heads have been united with an intervening spring, but without the capability of being lengthened or shortened except within the limits of the yield of the spring, thus necessitating the provision of various sizes of props at considerable expense and entailing the painful or disagreeable process of trying a number until the proper size is found. To obviate these disadvantages, I make one of the heads, as B, adj ustable toward and from the other, and this I accomplish by threading its shank and inserting it in a correspondingly threaded shell or section C. The shell 0 is mounted within or upon the head B, and is provided with a ledge a, which bears upon a spring I), interposed between it and head B. Being constructed, as so far explained, in order to vary the length of the implement, it is only necessary to revolve the shell C with respect to head B, as will be readily understood. This adjustment may be easily and quickly effected in whatever position the implement may be, and having been adjusted it may be used with all the advantages attending the use of the old forms having the yielding spring, but otherwise rigid or non-adj ustable. To facilitate adj 11stment, some part of the shell may be milled or roughened, but this is not material. The four partsthat is, the two heads, the shell or central section, and the spring-may be united in any suitable manner; but I prefer to connect them by an axial bolt, as 0, set in one head, and upon which the other may move. The head of the bolt will arrest the threaded head at the limit of its travel and prevent the parts from becoming accidentally separated; but the bolt being removable or detachable permits the parts to be disunited for cleaning or repairs, if required. The length of the bolt is preferably so graduated as to prevent the shell 0 from uncovering the spring. It may be made of any desired length, and it may be omitted, if desired. The head B may be turned farther than indicated in Fig. 3; but the further turning of it will have the effect of compressing spring I).

At 01 is a simple ring or wire for convenient application of a retaining-cord. This may be applied at any point, or may be omitted.

The improved implement takes the place of the longest and shortest props required, as well as any intermediate lengths. It is light, cheap, durable, and cleanly, and is found to admirably answer the purpose or object of the invention previously set forth.

Having now fully described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. In an implement of the character herein set forth, the cushion-heads combined with an intervening section and a yielding spring, one of the heads being made adjustable in or 

